Isotretinoin is a retinoid (also known as 13-cis retinoic acid). Owing to its low water solubility, the oral bioavailability of isotretinoin is low. PCT Publication No. WO 00/25772 discloses that the presently marketed formulation of isotretinoin, i.e., Accutane®, contains isotretinoin at a mean particle size of about 100 μm resulting in only 20% oral bioavailability.
U.S. Pat. Nos. 7,435,427 and 8,367,102 cover the marketed formulation of Absorica®. These patents disclose capsules comprising a semi-solid suspension of isotretinoin containing at least two lipidic excipients, one having an HLB value equal to or greater than 10 and the other being an oily vehicle. These patents are based on the use of the “Lidose® technology” to provide a formulation of isotretinoin with enhanced bioavailability.
Isotretinoin has a very high teratogenic potential. This drug may be prescribed only by or under the supervision of a consultant dermatologist. Therefore, reduction of dose in case of such a teratogenic drug is highly beneficial. Further, isotretinoin is known to have a “food effect”, i.e., its absorption is dependent on the presence of food in the stomach. Therefore, there is a need to develop a composition of isotretinoin which has a lower dose and reduced food effect. The present inventors have developed an oral pharmaceutical composition of isotretinoin, wherein said composition has enhanced bioavailability, lower dose and reduced food affect, in particular no food effect in comparison to the marketed formulations of isotretinoin, e.g. Roaccutane® and Absorica®. These advantages would lead to better patient compliance.
Further, the present inventors were able to develop an isotretinoin composition having low isotretinoin to excipient ratio which would allow for it to be filled in a capsule smaller than Absorica®. The smaller sized capsule would be advantageous for patients as it would be easier for swallowing.